Published on January 30, 2020   13 min
Hello, I'm Dr. Stephens. I'm clinical anatomist and a lecturer in anatomy from Cardiff University. Welcome to my talk on mediastinum.
So the learning outcomes for this talk are: By the end of the lecture, you should be able to; define mediastinum, understand major divisions of the mediastinum. You should be able to appreciate subdivisions of mediastinum and recognize and name the contents of the mediastinum.
So what is mediastinum? If you look at this image, you can see the central region is shaded green while the lungs and pleurae are shaded pink. So essentially mediastinum is that region within the thoracic cavity wherein if you remove the lungs and the pleurae, whatever is left behind would be the mediastinum. Essentially, on this diagram, if you take out the lungs and the pleurae which are shaded in purple on whatever is remaining, the green region in the center would be the mediastinum.
Boundaries of the mediastinum. So this is essentially the extent of the mediastinum. So vertically it extends from the superior thoracic aperture to the diaphragm and horizontally from the thoracic vertebrae to the body of the sternum.
Let's look at the divisions of the mediastinum. Mediastinum has got two major divisions, namely, the superior and inferior mediastinum. While the inferior mediastinum is subdivided into three, namely, the anterior media and the posterior mediastinum. Just to get the concept a bit more clearer, let refer to this diagram on the right. If you look here, you can see at the top, the region that is shaded green, which would be the superior mediastinum and all that region would be the inferior mediastinum, which is further divided into anterior mediastinum, which is shaded dark green here. Middle mediastinum, which is mainly the heart and the pericardium, which is shaded light blue here and that lies posterior to the heart and pericardium would be the posterior mediastinum.